ROME - Premier Silvio Berlusconi is steeped in a new scandal over a dinner he had at the home of a constitutional court judge who will rule on a key decision whether to grant him immunity from prosecution while in office.

Opposition lawmakers have called for the removal of the judge, Luigi Mazzella, and a colleague who participated in the mid-May dinner, saying there would never be any way to know whether Berlusconi influenced their deliberations on the immunity issue.

The court began debating the constitutionality of a law last month that grants Berlusconi, the Italian president and two parliament speakers immunity from prosecution. Berlusconi's forces had pushed the legislation through parliament last summer, saying it was necessary for the government to function.

At the time the bill was passed, Berlusconi was on trial on corruption charges in Milan, fueling criticism that the bill was tailor-made to save him from prosecution. The premier's trial was suspended pending a decision from the constitutional court, which is expected soon.

In an open letter Wednesday to the premier, Mazzella said that the dinner wasn't the first and wouldn't be the last with his "old friend" Berlusconi, saying it was his right to invite dear friends to dine whenever he wanted.

"Dear president, Dear Silvio," read the letter, which was read aloud on state-run RAI television Wednesday night.

Mazzella denounced the "barbarity" of news reports implying scandal, and said there was a "kilometres-long" list of his colleagues past and present who had dined with other high-ranking government officials.

Opposition lawmakers have expressed outrage over the dinner, which was first reported this week by the left-leaning newsweekly L'Espresso, charging that the court's impartiality was now called into question.

"We will never know if the decision of the constitutional court was the fruit of a total independent evaluation or was rather the fruit of a carbonara dinner," opposition lawmaker Antonio Di Pietro, a former anti-corruption prosecutor, said in parliament Wednesday.

He demanded the resignation of Mazzella and his colleague, Paolo Maria Napolitano, as well as the resignation of the Justice Minister Angelino Alfano, who also attended the dinner and for whom the immunity bill is named since he spearheaded it through parliament.

Cabinet minister Elio Vito defended the premier, saying Berlusconi hadn't organized any meeting about the legislation but was rather invited to a dinner by a friend well before the court began deliberating the case.

Di Pietro rejected the explanation, prompting another Culture Minister Sandro Bondi to storm out of parliament shouting "Shame on you! Shame on you!"

Berlusconi has long been dogged by conflict of interest allegations as well as corruption charges stemming from his years as a billionaire media mogul. He has either been acquitted - sometimes thanks to laws passed by his own government - or seen cases against him expire under the statute of limitations. He has always maintained his innocence, claiming he is the victim of a conspiracy of left-leaning magistrates.

The premier has been battling another scandal of late concerning reported parties at his own homes to which escorts were allegedly invited, and paid by an acquaintance, to attend. Berlusconi has said the reports were "garbage."